(1) Field of the Invention
The present invention pertains to a braking system for air conveyors. In particular, the present invention provides a braking system along the guide rails of an air conveyor that transports plastic bottles along a pathway between the guide rails. The braking system is selectively actuated to move into the pathway defined by the guide rails decreasing its width and positioning a stop of the braking system in the pathway where it will engage with bottles conveyed along the pathway by the air conveyor slowing and eventually stopping the bottles.
(2) Description of the Related Art
Air conveyors are typically employed in the rapid transport of empty plastic bottles of the type having an annular rim or a neck ring at the base of the bottle neck. A typical air conveyor includes a pair of flanges that are spaced from each other defining an elongated slot between the flanges. The spacing between the flanges is sufficiently large to enable a portion of the bottle just below the neck ring to pass through the spacing with the bottle suspended from the top surfaces of the flanges by the neck ring engaging on the top surfaces. A series of air ducts are positioned along the flanges above and/or below the elongated slot. A plenum of the air conveyor supplies a flow of air to the air ducts. The air ducts are oriented so that air ejected from the ducts will contact the plastic bottles pushing the bottles along the pathway defined by the elongated slot with the neck rings of the bottles sliding along the top surfaces of the spaced flanges.
Preferably, air conveyors transport bottles in closely spaced succession and at a substantial speed. A typical air conveyor is constructed with both straight sections and curved sections in order to transport the succession of bottles from one area to another. Air conveyors often have guide rails positioned below the slot defined by the pair of flanges. Pairs of guide rails positioned on opposite sides of the slot follow the conveyor path defined by the slot. The guide rails are usually spaced further apart from each other than are the flanges to allow the width of a bottle suspended from the flanges to pass easily between the guide rails. The guide rails limit the side-to-side movement of the succession of bottles conveyed by the air conveyor and thereby limit the extent to which the body of the bottle can swing outwardly or transversely from the air conveyor path, for example when the air conveyor rounds a curve, and thereby avoids a bottle neck or neck ring potentially becoming jammed in the air conveyor slot and stopping the succession of conveyed bottles.
With a typical air conveyor being capable of transporting a large succession of plastic bottles at a considerable speed, problems can be encountered when a large succession of bottles are stopped and accumulated at the end of the air conveyor. In prior art air conveyors, the leading bottle in a succession would be stopped at the end of the air conveyor by a selectively operated gate mechanism. This first bottle stopped by the gate mechanism would in turn stop all subsequent bottles that trailed it in the line of succession of bottles conveyed by the air conveyor. Thus, this first stop bottle would have a force exerted on it by each of the trailing bottles conveyed by the conveyor mechanism. With a long line of succession of bottles, the force exerted on the first stopped bottle could be sufficient to damage the bottle. In a like manner, the second 20 bottle in the sequence has a force exerted on it by each of its trailing bottles. This force could also be sufficiently large in a long succession of bottles to cause damage. In this manner, several bottles at the forward end of a long succession of bottles stopped by the conveyor system could be damaged. In addition, when the air conveyor is conveying a large number of bottles in a group and they come to one or more bottles stopped by the gate of the air conveyor, the impact of the large group of conveyed bottles with the stopped bottle or bottles can cause the forward most stop bottle to be forced through the gate.
To overcome this problem, a mechanism is needed that not only engages with the forward most bottle in a succession of bottles to stop the succession of bottles, but engages with and brakes several of the bottles in the succession of bottles. In addition, it is desirable that the mechanism have a simplified construction that would enable it to be retrofit to an existing air conveyor at several spots along the length of the air conveyor to enable stopping groups of bottles conveyed by the air conveyor at controlled points along the air conveyor length to thereby control the number of bottles that would accumulate at any one position along the length of the air conveyor where the succession of conveyed bottles are stopped.